Cancer of the colon is a highly treatable and often curable disease when localized to the bowel. It is one of the most frequently diagnosed malignancies in the United States as well as the second most common cause of cancer death. Surgery is the primary treatment and results in cure in approximately 50% of patients. However, recurrence following surgery is a major problem and often is the ultimate cause of death.
The prognosis of colon cancer is clearly related to the degree of penetration of the tumor through the bowel wall and the presence or absence of nodal involvement. These two characteristics form the basis for all staging systems developed for this disease. Treatment decisions are usually made in reference to the older Duke's or the Modified Astler-Coller (MAC) classification scheme for staging.
Bowel obstruction and bowel perforation are indicators of poor prognosis in patients with colon cancer. Elevated pretreatment serum levels of carcinoembryonic antigen (CEA) and of carbohydrate antigen 19-9 (CA 19-9) also have a negative prognostic significance.
Age greater than 70 years at presentation is not a contraindication to standard therapies. Acceptable morbidity and mortality, as well as long-term survival, are achieved in this patient population.
Because of the frequency of the disease (approximately 160,000 new cases of colon and rectal cancer per year), the identification of high-risk groups, the demonstrated slow growth of primary lesions, the better survival of early-stage lesions, and the relative simplicity and accuracy of screening tests, screening for colon cancer should be a part of routine care for all adults starting at age 50, especially those with first-degree relatives with colorectal cancer.
Procedures used for detecting, diagnosing, monitoring, staging, and prognosticating colon cancer are of critical importance to the outcome of the patient. For example, patients diagnosed with early colon cancer generally have a much greater five-year survival rate as compared to the survival rate for patients diagnosed with distant metastasized colon cancer. New diagnostic methods which are more sensitive and specific for detecting early colon cancer are clearly needed.
Colon cancer patients are closely monitored following initial therapy and during adjuvant therapy to determine response to therapy and to detect persistent or recurrent disease of metastasis. There is clearly a need for a colon cancer marker which is more sensitive and specific in detecting colon cancer, its recurrence, and progression.
Another important step in managing colon cancer is to determine the stage of the patient's disease. Stage determination has potential prognostic value and provides criteria for designing optimal therapy. Generally, pathological staging of colon cancer is preferable over clinical staging because the former gives a more accurate prognosis. However, clinical staging would be preferred were it at least as accurate as pathological staging because it does not depend on an invasive procedure to obtain tissue for pathological evaluation. Staging of colon cancer would be improved by detecting new markers in cells, tissues, or bodily fluids which could differentiate between different stages of invasion.
Accordingly, there is a great need for more sensitive and accurate methods for the staging of colon cancer in a human to determine whether or not such cancer has metastasized and for monitoring the progress of colon cancer in a human which has not metastasized for the onset of metastasis.
In the present invention, methods are provided for detecting, diagnosing, monitoring, staging, prognosticating, imaging and treating colon cancer via a colon specific gene referred to herein as CSG. For purposes of the present invention, CSG refers, among other things, to native protein expressed by the gene comprising a polynucleotide sequence of SEQ ID NO: 1. By “CSG” it is also meant herein polynucleotides which, due to degeneracy in genetic coding, comprise variations in nucleotide sequence as compared to SEQ ID NO: 1 but which still encode the same protein. In the alternative, what is meant by CSG as used herein, means the native mRNA encoded by the gene comprising the polynucleotide sequence of SEQ ID NO: 1, levels of the gene comprising the polynucleotide sequence of SEQ ID NO: 1, or levels of a polynucleotide which is capable of hybridizing under stringent conditions to the antisense sequence of SEQ ID NO: 1. SEQ ID NO: 1 is also referred to as Cln106.
Other objects, features, advantages and aspects of the present invention will become apparent to those of skill in the art from the following description. It should be understood, however, that the following description and the specific examples, while indicating preferred embodiments of the invention are given by way of illustration only. Various changes and modifications within the spirit and scope of the disclosed invention will become readily apparent to those skilled in the art from reading the following description and from reading the other parts of the present disclosure.